Did I understand Twin Paradox?

Question

If my understanding is correct I don't see a paradox in Twin Paradox. for the twin traveling in the space ship, time will dilate and he would have spent 20 years in flight, and the other twin on earth would have also spent 20 years, only change would be that the clock would have progressed 10 years rather than 20 years, literally it's just like timezone travel i.e. there is not time lost. Please correct my understanding

Answer 1

The detail that you are missing is that each observer will see the clocks of the other twin running more slowly - as long as they are moving at a constant relative speed. So the twin on Earth will see his traveling twin aging more slowly. And the twin on the spacecraft will see his twin on Earth aging more slowly. They will both be correct. In this scenario, neither twin has any way of determining which twin is "standing still" and which twin is "moving."



The thing that alters this situation so that only the traveler ages more slowly is the fact that he accelerates and decelerates - when he leaves the Earth, when he turns around to return, and when he finally slows to a landing. This establishes his reference frame as the one that moves relative to the Earth's reference frame. This results in his clocks accumulating less time over the duration of the journey than the clocks of his twin brother.



The math to demonstrate this is not as straightforward as the standard Lorentz Transform application to two inertial frames. In fact, the difficulty of accelerated frames led to Einstein's masterwork on General Relativity. It took him ten more years of hard work.



ADDED: I should clarify a bit. The "paradox" is not that each observer will see the clock of the other observer running more slowly. That is an effect of the Lorentz Transformation being applied to each reference frame in turn. This is not well understood by the general public, and it represents a paradox to those who are not familiar with it. It is not really a paradox; it is just the way the universe works. The paradox as referred to here is simply the idea that a twin can return to find that he has aged less than his brother due to the effects of Special and General Relativity on the reference frames in question and the fact that time proceeds at a different rate in each frame relative to the other. That's why it's called the Twin Paradox. Oklatonola is correct.

Answer 2

The clock with the traveling twin, that measures out 10 years, is measuring out time exactly as the traveling twin experiences it. Not only will the clock have measured 10 years, but that twin will have experienced 10 years of life by the time he comes back, and will have aged only 10 years to the other twin's 20 years. Everything that travels with him slows down. For instance, if he took with him a lump of decaying radioactive material and left an equivalent lump on Earth, then when he got back, the one he left behind would have decayed farther than the one he took along. It's a real physical effect.



This is not the same as adjusting a clock for time zone travel, which is merely done for convenience and has no physical significance.

Answer 3

Oklatonola, wrong again...please stop.



Time dilation in Special Relativity is not a paradox. Maybe in a geology class, but not in SR.

The paradox apparently appears due the fact that each observer views the others clock running slow.



Good job to Larry454, I never see anybody actually know this paradox.



ADD:



Nevermind. I guess you proved me wrong. Larry, Oklatonifadof whatever is wrong. What you said originally is correct. What you added is incorrect. The apparent paradox is not that the twin that left and came back is younger or aged "slower". Time dilation is not a paradox or was it ever considered a paradox. The paradox arises from naively and incorrectly assuming symmetry of both reference frames. In the incorrect application, each observer observes the others clock running slow for the WHOLE TRIP. This suggests that from each reference frame, everybody is experiencing some equal amount of time dilation. We would assume from SR that since the twin that moving he/she would be the one that experienced the time dilation, but the apparent paradox is that yes, they should both agree that one who left is younger; but SR applied symmetrically to each frame of reference they shouldn't agree on that.



It is not a paradox because of what you originally said, each case is not symmetric. This is easily seen in a spacetime diagram of the the events in question and is a VERY important example of non-euclidean geometry in a Minkowski space.



See any GR or SR text.

Answer 4

No, it is like this:

The twin on Earth sees the clock of the twin traveling running slower than the one he has on Earth, while the twin on the space ship sees the clock on Earth running slower than his own clock in the space ship. In other words, each one sees the other one's clock to be running slower than his own clock. So when the one who traveled away and back returns, who's clock turns out to have recorded less time while the traveling twin was traveling? And don't get hung up on the clocks. The theory doesn't say the clocks change; it says time itself changes; both clocks operate normally and measure it correctly.

Answer 5

It's time dilation. When the twin who was on the space ship comes back and meets the twin who stayed home on Earth, the twin on the space ship will have aged only 20 years physiologically (his body would be 20 years older) years, while the twin who stayed on Earth ages 60 or more years physiologically.

Answer 6

it is paradoxical because of the fact the two twins could p.c. the different twin as shifting, on the grounds that action is relative. even nevertheless, acceleration isn't relative, so the twin in area a while extra slowly.

Answer 7

You mis -understand.

That 'clock' measures time as experienced by the twin holding it.

The stationary twin ages twenty years, the moving one, ten.